Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userMeasurement of beta_s at CDF
101
0
0.0
(
0
)
Authors
Louise Oakes
Ask ChatGPT about the research
No Arabic abstract
The latest results for the measurement of the CP violating phase beta_s in B0s -> J/psi phi decays, from 5.2 fb-1 integrated luminosity of CDF data are presented. For the first time, this measurement includes the contribution of B0s -> J/psi K+K- or B0s -> J/psi f0 events to the signal sample, where the f0 and non-resonant K+K- are S-wave states. Additional improvements to the analysis include more than doubling the signal sample, improved selection and particle ID, and fully calibrated flavour tagging for the full dataset. Additionally, the worlds most precise single measurements of the B0s lifetime, tau_s, and width difference, DeltaGamma_s are given.
rate research
Read More
We present a measurement of the CP-violating parameter betas using approximately 6500 $BsJpsiPhi$ decays reconstructed with the CDF,II detector in a sample of $pbar p$ collisions at $sqrt{s}=1.96$ TeV corresponding to 5.2 fb$^{-1}$ integrated luminosity produced by the Tevatron Collider at Fermilab. We find the CP-violating phase to be within the range $betas in [0.02, 0.52] cup [1.08, 1.55]$ at 68% confidence level where the coverage property of the quoted interval is guaranteed using a frequentist statistical analysis. This result is in agreement with the standard model expectation at the level of about one Gaussian standard deviation. We consider the inclusion of a potential $S$-wave contribution to the $Bsto J/psi K^+K^-$ final state which is found to be negligible over the mass interval $1.009 < m(K^+K^-)<1.028 gevcc$. Assuming the standard model prediction for the CP-violating phase betas, we find the Bs decay width difference to be $deltaG = 0.075 pm 0.035,textrm{(stat)} pm 0.006,textrm{(syst)} ps$. We also present the most precise measurements of the Bs mean lifetime $tau(Bs) = 1.529 pm 0.025,textrm{(stat)} pm 0.012,textrm{(syst)}$ ps, the polarization fractions $|A_0(0)|^2 = 0.524 pm 0.013,textrm{(stat)} pm 0.015,textrm{(syst)}$ and $|A_{parallel}(0)|^2 = 0.231 pm 0.014,textrm{(stat)} pm 0.015,textrm{(syst)}$, as well as the strong phase $delta_{perp}= 2.95 pm 0.64,textrm{(stat)} pm 0.07,textrm{(syst)} textrm{rad}$. In addition, we report an alternative Bayesian analysis that gives results consistent with the frequentist approach.
We present improved bounds on the CP-violating phase beta_s^{Jpsiphi} and on the decay-width difference DeltaGamma of the neutral B_s^0 meson system obtained by the CDF experiment at the Tevatron collider . We use 6500 B_s^0 --> J/psi phi decays collected by the dimuon trigger and reconstructed in a sample corresponding to integrated luminosity of 5.2 fb-1. Besides exploiting a two-fold increase in statistics with respect to the previous measurement, several improvements have been introduced in the analysis including a fully data-driven flavour-tagging calibration and proper treatment of possible S-wave contributions.
We present preliminary results on inclusive direct photon production in $pbar{p}$ collisions at $sqrt{s}$=1.96 TeV, using data collected with the upgraded Collider Detector at Fermilab in Run II, corresponding to an integrated luminosity of 451 pb$^{-1}$. Measurements are performed as a function of the photon transverse momentum for photons with $p_{T}>$30 GeV and $|eta|<$1.0. Photons are required to be isolated in the calorimeter. The measurement is corrected to the hadron level and compared to NLO pQCD predictions.
We present a measurement of the mass difference between top ($t$) and anti-top ($bar{t}$) quarks using $tbar{t}$ candidate events reconstructed in the final state with one lepton and multiple jets. We use the full data set of Tevatron $sqrt{s} = 1.96$ TeV proton-antiproton collisions recorded by the CDF II detector, corresponding to an integrated luminosity of 8.7 fb$^{-1}$. We estimate event-by-event the mass difference to construct templates for top-quark signal events and background events. The resulting mass difference distribution of data compared to signal and background templates using a likelihood fit yields $Delta M_{top} = {M}_{t} - {M}_{bar{t}} = -1.95 $pm$ 1.11 (stat) $pm$ 0.59 (syst)$ and is in agreement with the standard model prediction of no mass difference.
We present a measurement of the top quark mass (Mtop) in the all-hadronic decay channel using 5.8 fb^{-1} of proton-antiproton data collected with the CDF II detector at the Fermilab Tevatron Collider. Events with 6 to 8 jets are selected by a neural network algorithm and by the requirement that at least one of the jets is tagged as a b quark jet. The measurement is performed by a likelihood fit technique, which determines simultaneously Mtop and the jet energy scale (JES) calibration. The fit yields a value of 172.5 +- 1.4(stat) +-1.0(JES) +-1.1(syst) GeV/c^2.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
